Ore flotation



Patented June 7, 1938 UNITED STATES- PATENT OFFICE No Drawing.Application December 18, 1937, Serial No. 180,639

45C'laims.

My invention relates to the separation of mineral constituents of oresby flotation and related processes such as agglomeration.

The froth flotation of sulphide ores has reached a fairly high stage ofdevelopment and is successfully practiced today with the use of variousagents, particularly the xanthates. The concentration of the mineralvalues in the non-sulphide ores is still a major problem so far asflotation is concerned although, in the past few years, some newflotation agents have been developed which are somewhat efiective inthis field.

My invention involves the utilization of new flotation agents which arehighly eifectlve in the froth flotation of both sulphide andnon-sulphide ores and permit the production of relatively pureconcentrates with a high percentage of recovery of desired mineralvalues.

My invention is also concerned with modifying .the surfacecharacteristics of the ore to permit the separation of constituentsthereof by the wellknown agglomeration or granulation method, of whichthe Cattermole and Murex processes are illustrative, wherein the oreparticles are selectively oiled and wherein the separation is effectedby tabling as, for example, on a Wilfley table.

One object of my invention is, accordingly, the provision of a new classof reagents which are highly effective in flotation and agglomerationprocesses.

Another object is the provision of improved flotation frothing andfoaming agents which will, in general, perform and function in eitheracid or alkaline media.

A further object is the provision of a flotation process which may beemployed in the flotation of non-sulphide ores.

Still another object of my invention is the provision of novelprocedures for effectively separating mineral values from ganguematerials associated therewith in ores and the like by froth flotationand agglomeration procedures.

Still another object of my invention relates to effectively separatingsoluble salts from each other by either froth flotation or agglomerationmethods.

Other objects and features of the invention will become apparent as thedescription proceeds.

In froth flotation one constituent of an ore is selectively modified bythe reagents added. These reagents may modify the mineral surface bychemical action or adsorption or both or may modify the interfacialrelations with the liquid. In most cases, it is the function offlotation reagents to so modify interfacial relationships that themineral particles to be floated are water repellent. Another function offlotation reagents is to produce a froth in which the selectivelymodified mineral will be included.

In agglomeration or granulation methods of separation, which methods Iinclude within the scope of the term flotation", the selectivelymodified mineral-liquid interface is wetted with an oleaginous substanceto produce or increase water repellency and" the water repellent oilparticles are then separated by mechanical means such as a conventionalore dressing table. In this type of separation, the frothing elementnecessary in froth flotation procedures need not be present. I havefound, however, that it is sometimes advantageous to separateselectively oiled particles by froth flotation and this may be readilydone in most cases by the addition of a frothing agent if the particlesare not too large. It will be seen, therefore, that the initial steps inagglomeration and flotation processes .are fundamentally the same,namely, the production of a selectively modified interfacialrelationship between the minerals and the liquid surrounding them, theonly difl'erence being in the particular method employed for effectingthe actual-separation of the mineral particles whose surfaces have beenmodified. a

In my Patent No. 1,917,250, I have disclosed a class of chemicalsubstances which I have found can be used with satisfaction intheflotation of ores and minerals. The chemical substances disclosed insaid patent have been described as being possessed of certain groupingswhich impart to the resulting molecule emulsifying, frothing,penetrating, and, in general, surface modifying properties whereby theymay be used for various purposes. In said patent, I have shownsaidchemical substances to have particular utility as emulsifying agents andas addition agents in the manufacture of margarine, to which latterproduct they impart the property of substantial decrease in itsspattering behavior when it is heated in an open pan. I refer thoseskilled in the art not only to my aforementioned patent but also torelated Patents Nos. 1,917,251; 1,917,252; 1,917,255; 1,917,256;1,917,257; 1,917,258; 1,917,259f and 1,917,260, for a more completediscussion of the characteristics of these substances and representativeprocesses for preparing them.

In general, the classes of substances which I have discovered can beeffectively employed as flotation agents in accordance with my presentinvention are characterized by the presence of both lipophile andhydrophile groups in the same molecule in a state of "balance". Theimportant characteristics which distinguish the compounds which I employherein are intimately related to the role which the substances play inthe present invention. They are all either freely soluble in aqueousmedia or dispersible therein. Many of them are also rather freelydispersible in oleaginous media due to the dual character of themolecule, namely, the presence therein of both lipophile and hydrophilegroups.

It will be understood that I employ the term hydrophile group" toinclude groups which possess affinity for water and aqueous media. Asexamples of such groups may be mentioned the following: hydroxy,sulphate, sulphonic, phosphate,-pyrophosphate, tetraphosphate, lowermolecular weight sulpho-carboxylic acids such as sulpho-acetates,sulpho-propionates, etc., and quaternary ammonium or other hydrophilicnitrogenous or non-nitrogenous groups.

Contrasting'ly, the lipophile group is a group having a definiteaffinity for oils and fats and comprises, for example, either an alkyl,aralkyl, aryl, ether or ester group. The lipophile group possessespredominantly hydrocarbon characteristics and, in general, is derivedfrom fats, oils, waxes, mineral oils, other hydrocarbons and the like.

The lipophile group with its marked amnity for oils and fats generallycauses the molecule of which it is a part to orientate itself so thatthe lipophile group is in relatively closer proximity to the oil mediumor phase as contrasted with the aqueous medium in oleaginous-aqueousemulsions.

For my present purposes, namely, for ore separation treatments, thechemical substances which I employ must possess sumcient lipophile massand quality in order properly to ofiset and "balance the hydrophilegroup. Anexcess of either lipophile characteristics or hydrophilecharacteristics is undesirable because the substance then tends tobecome either predominantly lipophilic or predominantly hydrophilic andin neither case will the most satisfactory results attend the usethereof in ore separation processes. The so-called balance of' the twogroups, namely, the lipophile and the hydrophile groups, in the moleculemay be determined empirically by means of a margarine frying test asdescribed in my prior Patent No. 1,917,250. However, in most cases,those skilled in the art will be able to select substances coming withinthe class suitable for my present purposes from merely an inspection ofthe molecule of the compound itself.

In general, the lipophile or non-polar group of my compounds shouldcontain at least eight carbon atoms, although, in some specific cases,compounds having as low as four carbon atoms in the lipophile group areof utility for special purposes, this being dependent, in part, upon thespecific character of the lipophile group present in the molecule, aswell as upon the location of the two groups in the molecule. As ageneral rule, the hydrophile and lipophile groups should preferably beat the ends or extremities of the molecule as, for example, in the caseof palmityl sodium sulphate wherein the palmityl group or, in otherwords, the lipophile group, is present at one end of the molecule andthe sulphate or bydrophile group is present at the other end of themolecule.

Among the compounds the use of which for ore separation purposes fallswithin the scope of my invention are organic chemical substances havingbalanced lipophile and hydrophile groups, the lipophile group containingat least eight carbon atoms and the hydrophile group comprising aradical selected from the class consisting of oxygenated sulphur andoxygenated phosphorus inorganic acid radicals. One sub-class thereofwhich I have found to be particularly useful for the separation ofmineral values from associated gangue material is the higher molecularweight alkyl sulphates and sulphonates such as heptyl sulphate, octylsulphate, nonyl sulphate, decyl sulphate, dodecyl or lauryl sulphate,myristyl sul phate, cetyl sulphate, oleyl sulphate, ricinoleyl sulphate,linoleyl sulphate, palmitoleyl sulphate, stearyl sulphate, cerylsulphate, myricyl sulphate, mellssyl sulphate, branched chain higheralcohol sulphates including the sulphates of branched chain octyl,decyl, dodecyl, tetradecyl, hexadecyl and octadecyl aliphatic alcoholsas, for example, 2-ethyl hexanol-l, 2-n butyl octanol-l,3-ethylhexanol-l, and the like, preferably employed in the form of theiralkali metal salts, by which I include not only the sodium and potassiumsalts but also the ammonium salts. In general, the sulphates of thenormal straight-chain saturated and unsaturated primary aliphaticalcohols having between 8 and 18 carbon atoms are most satisfactory. Thealcohols from which these sulphates are prepared may be produced in anysuitable manner as, for example, by the reduction of the correspondingfatty esters in accordance with the Bouveault-Blanc method or,alternatively, by the reduction or catalytic reduction with hydrogen ofnatural or hydrogenated animal or vegetable fats and oils in accordancewith well known practices. Again, the alcohols may be derived fromsynthetic processes such as by the oxidation of hydrocarbons or may beprepared by saponification of waxes and the like. Alternatively, theymay be prepared by reduction of aldehydes or'by the Grignard reaction.Still other methods known in the literature may be employed if thoughtdesirable or expedient. It is likewise apparent that mixtures of theforegoing or other alcohols may be sulphated or sulphonated and employedas flotation or ore-treating agents in accordance with the teachings ofmy invention as, for example, the mixture of alcohols resulting from thehydrogenation of coconut oil or the free fatty acids of coconut oil.Lauryl alcohol comprises about 60% of the total alcohol mixture, theremaining alcohols running from C6 to C18. (See German Patents D 56471IV/ of August 30, 1928, and D 56488 IV/l20 of September 4, 1928, forreduction with hydrogen of oils and fats and free fatty acids to producealcohols.) Again, mixtures of alcohols such as are present in theso-called sperm-oil alcohols, as well as those present in wool fat, mayalso be sulphated or sulphonated and employed in ore-treating operationsin accordance with my invention. Indeed, these higher molecular weightalcohols are generally, if, indeed, not almost invariably, offered onthe market in the form of mixtures of different alcohols. If desired forany specific purpose, special fractions which predominate in a certainparticular higher molecular weight alcohol may be utilized or, if sodesired, the sulphates or sulphonates may be prepared from a single,substantially pure alcohol.

As I have indicated, I may utilize the sulphonates of the highermolecular weight alcohols as distinguished from the sulphates thereof.In

other words, I may employ such compounds as octyl sulphonic acid, decylsulphonic acid, lauryl sulphonic acid, cetyl sulphonic acid, and, ingeneral, the sulphonic acid derivatives corresponding to theabove-mentioned sulphates, preferably in the form of their alkali metalor ammonium salts.

The sulphates and sulphonates described above may be represented by thegeneral formula wherein R is a radical containing a hydrocarbon chain ofat least eight carbon atoms, X is a sulphuric or sulphonic group presenton the extremity of the radical represented by R, and Y is the radicalof a salt-forming compound. In a more specific aspect of my invention,B. may represent the residue of a normal primary alcohol containing atleast eight carbon atoms.

In a still more specific aspect of this phase of my invention, thesulphates may be represented by the general formula wherein R representsthe residue of a normal primary alcohol containing from 8 to 18 carbonatoms, and Y represents the residue of a salt-forming compound such assodium.

Another sub-class of compounds useful for flotation purposes are thosecompounds which correspond to the higher alkyl sulphates and sulphonatesdescribed above but wherein the hydrophile group comprises oxygenatedphosphorus instead of oxygenated sulphur. Among these compounds may bementioned lauryl phosphate, palmityl phosphate, sodium palmitylphosphate, stearyl phosphate, oleyl phosphate, calcium palmitylphosphate, monocholesteryl dihydrogen orthophosphate, dicholesterylhydrogen orthophosphate, ceryl dihydrogen orthophosphate, melissylphosphate, melissyl calcium phosphate, dipalmityl sodium orthophosphate,and the like. As in the case of the sulphates and sulphonates describedpreviously, it is generally preferred to employ the oxygenatedphosphorus derivatives in the form of their alkali or. ammonium salts.

A further sub-class of compounds, useful for ore separation processes,are compounds having balanced lipophile and hydrophile groups andcomprising derivatives of polyhydroxy substances through which arelinked lipophile and hydrophile radicals. In general, these compoundsare relatively high molecular weight aliphatic or fatty ethers andesters of polyhydroxy substances wherein a hydrophile group, such as anoxygenated inorganic acid radical, is attached to the polyhydroxynucleus. More specifically, these compounds may take the form of higherfatty acid esters of aliphatic polyhydric alcohols wherein the hydrogenof at least one of the remaining hydroxy groups of the polyhydricalcohol is replaced by a sulphate, a lower molecular weightsulpho-carboxylic acid or a phosphate radical. Among such compounds maybe mentioned, by way of illustration, monostearin sodium sulphoacetate,mono-oleic acid ester of diethylene glycol sulphoacetate, monostearicacid ester of diethylene glycol sodium sulpho-acetate, dodecyldiethylene glycol ether sulphate (monoethanolamine salt), stearyldiethylene glycol dihydrogen orthophosphate, lauryl diethylene glycolammonium sulphate, monolauryl sulphoacetate, sulphates of ethers ofdiethylene glycol sulphate (neutralized with sodium, potassium,

ammonium or the like) mixed coconut oil fatty acid mono-esters ormono-oleic acid ester of glycerol mono-sulphate (neutralized asindicated), sodium salt of the sulphate of diethylene glycol monobutylether, ammonium salt of oleyl and stearyl diethylene glycol, sodium saltof mono-ncaprylil diethylene glycol sulphate, monoethanolamine salt ofthe sulphate of diethylene glycol monobutyl ether, mono-oleindisulphate, sulphate of the mono-oleic acid ester of diglycerol,sulphates of mono-fatty acid esters of glycerol such as monostearinmono-sulphate, and the like. For an even more complete disclosureofcompounds of this type, reference may be had to my Patents No.2,023,387, issued December 3, 1935 and No. 2,026,785, issued January 7,1936, and to my copending application, Serial No. 627,096, filed July30, 1932.

Other compounds having utility for my purposes, and possessing balancedlipophile and hydrophile groups, are the lower molecular weight laurylsulphoacetate, lauryl sulpho-propionate,

myristyl sulphoacetate, cetyl sulphoacetate, choles teryl sulphoacetate,oleyl sulphoacetate, stearyl sulphoacetate, ricinoieyl sulphoacetate,linoleyl sulphoacetate, p-ethyl-hexyl sulphoacetate, and the like,preferably in the form of their alkali metal, ammonium, or organicamine, such as ethanolamine, salts.

A further subclass of compounds having utility in ore separatingtreatments, and having balanced lipophile and hydrophile groups, arecertain derivatives of polyhydroxy substances or polyhydroxycarboxylicacids including, for example, such compounds as monostearic acid esterof dextro'se, mono-stearic acid ester of sucrose, mannitolmono-palmitate, stearyl tartaric acid, mucic acid mono-palmitate,stearyl malic acid, digitonincholesteride, and the like. For a furtherdisclosure of such compounds, reference may be had to my Patent No.1,917,257, above mentioned, and to my Patent No. 2,025,984, issuedDecember 3, 1935.

Still another group of reagents which I have I found effective for mypresent purposes, and falling within the class of organic chemicalsubstances having balanced lipophile and hydrophile groups with alipophile group having at least eight carbon atoms, are organicnitrogenous substances. These compounds include organicnitrogen-containing haloides having a hydrocarbon group of at leasteight and preferably at least twelve carbon atoms and, morespecifically, aliphatic derivatives of anion-containing heterocycliccompounds such as aliphatic hydrocarbon derivatives of pyridiniumhalides such as pyridinium chloride or bromide. Among the specificcompounds falling within this class may be mentioned, by way ofillustration, cholesteryl ester of betaine hydrochloride,(carbocholesteroxy) methyl trimethylammonium chloride, cholesteryl esterof betaine hydrobromide, palmityl ester of betaine hydrochloride orhydrobromide, (carbopalmitoxy) methyl pyridinium bromide, melissyl esterof betaine hydrobromide, (carbocholesteroxy) methyl pyridinium bromide,(carbocholesteroxy) methyl dimethylphenyl ammonium .bromide,(carbocholesteroxy) methyl quinaldinium bromide, cholesteryldimethylwithin this sub-class may be found in my Patent No. 2,023,075,issued December 3, 1935.

For the preparation of the higher aliphatic or higher fatty acid estersdescribed hereinabove, such as monostearin sulphate, monolauric acidester of diethylene glycol, and the like, the term "higher beingemployed to mean at least eight carbon atoms, the following acids may beemployed as well as mixtures thereof: saturated and'unsaturatedaliphatic and fatty acids including capryiic, capric, stearic acid,hydroxystearic acid, oleic acid, lauric acid, myristic acid, coconut oilmixed fatty acids, linoleic acid, ricino- .ieic acid, palmitic acid,melissic acid; and mixed higher fatty acids derived from animal andvegetable oils and fats, whether hydrogenated or not, such as cottonseedoil, corn oil, soya bean oil, sesame oil, fish oils, lard, oleo oil, andothers, such as the fatty acids derived from waxes like beeswax andcarnauba wax.

I have mentioned hereinabove that the sulphates, sulphonates and otheroxygenated suiphur and phosphorus derivatives are preferably employed inthe form of their alkali metal or ammonium salts. In certain instances,other cations may be present in place of sodium, potassium or ammonium,as, for example, calcium, magnesium, aluminum, zinc, and organiccationicfunctioning or neutralizing compounds such as the aliphatic andaromatic amines including, for example, tertiary amines, pyridine,quinaldine, alkylolamines such as mono-, diand triethanolamine andmixtures thereof, quaternary ammonium bases such as tetra-methyl andtetraethyl ammonium hydroxide, and the like.

While flotation reagents may be classified in general into frothers andcollectors, this classification is not particularly useful in describingmy invention since, under different conditions, these reagents may fallinto one or both classiflcations. In general, reagents of the classesdescribed hereinabove possess frothing properties in at least somedegree and, in many cases, certain of these compounds may be used asfrothers with the exertion of a minimum of influence on the flotationcircuit other than to provide the necessary volume of froth. In othercases, the compounds function simultaneously as frothers and collectors.As an illustration, compounds of the type of lauric acid ester ofdiethylene glycol ammonium sulphate are highly selective collectors andmay be used in conjunction with other agents without interfering withthe selective properties thereof. On the other hand, lauric acid esterof diethylene glycol ammonium sulphate and similar compounds functionboth as frothers and collectors for the separation of such minerals ascalcite and apatite from less readily floatable minerals. Again, thehigher molecular weight alkyl sulphates are excellent frothing agentsand, in many instances, also function as collecting agents.

As previously described, the reagents which I employ herein selectivelymodify the interface relationship of certain minerals so that they maybe oiled and separated by either froth flotation methods oragglomeration and tabling. In some cases of agglomeration procedures,the oiling is not necessary. Where oiling is employed, it may be donesimultaneously with the addition of the selectiveinterface modifyingagents or the oiling may be carried on subsequently in a separate step.

Since the reagents which I employ herein possess good emulsifying anddispersing power, they may be advantageously used to prepare emulsionsof petroleum oils, kerosene, vegetable and animal oils, normally solidor liquid higher fatty acids, and to prepare dispersions of otherlipophilic solids such as metallic soaps and xanthates. These emulsionsor suspensions are useful as collecting agents and the like in theflotation and agglomeration of minerals. I'hese emulsions may beprepared by any of the several methods known in the art. For example,the flotation agents of my invention may be admixed with a small amountof water in a mortar and then oil may be gradually added whilecontinuously stirring or mixing until emulsiflcation is initiated. Theoil may then be added more quickly until the formation of the emulsionis completed. It will be understood, of course, that the stability ofthe emulsion will be affected by various factors including the relativeproportions of the flotation agent, water, and oil or the like, thespecific type of agent and oil or the like, the pH, and the exact methodof preparation. In general, the

oil-in-water type of emulsions produces superior results.

I shall now describe the manner in which the novel flotation agents maybe used in the actual separation of mineral values from ores containingthe same by froth flotation as well as by agglomeration methods.

Example I In the concentration of tungsten ore containing scheelite,calcite and quartz, the ore was ground to 100 mesh, the grinding beingcarried out preferably to keep the amount of lines as low as possible.The ore was then acidified to the extent of about 1.0 lb. of sulphuricacid per ton of pulp. 0.25 lb. of oleic acid per ton of ore and 0.25 lb.of lauric acid ester of diethylene glycol ammonium sulphate per ton ofore were added and the pulp subjected to froth flotation. The frothwhich contained only calcite was first removed. The acidity was thenreduced to about 0.4 lb. per ton of pulp by the addition of caustic sodaand the flotation was then continued. The concentrate and tailingobtained in this flotation is shown by the following table:

Weight; A per can ssa Product of on? Domain Recovery inal ore W0;

Concentrate 3. 6 65. 2 03. 6 a ng 74.9 0.04 1.2 Original 01's.... 2. 50

Example II In the treatment of a complex lead-zinc-iron sulphide orefrom Utah, having the composition-lead 8.8%, zinc 9.7%, iron 28.2%, andthe remainder silica and silicates, the ore was ground to pass a 60 meshscreen and was made into a pulp containing 20% solids. The pulp was thenconditioned with 2.0 lbs. of sodium carbonate per ton and then subjectedto froth flotation using as a reagent an aqueous emulsion containing1.0% of lauric acid ester of diethylene glycol ammonium sulphate and 2%of corn oil. An amount of this reagent was initially added to give 0.2lb. of the lauric acid ester of diethylene glycol ammonium sulphate perton of ore. The

mineralized froth which formed immediately was removed as concentrateNo. 1. Additional emulsion to double the original amount was then addedand lifter several minutes further mineralized froth formed, this beingremoved as concentrate No. 2. .When no more mineral appeared in thefroth, 0.2 lb. of copper sulphate per ton of ore was added and anotherconcentrate removed which was designated as No. 3. The mineral remainingin the machine was removed as tailings. The analysis of the concentratesand tailings is shown in the following table:

l ko'rrr FLOTATIONUTAH COMPLEX Oar: Head analysis lead 8.8%--zinc9.7%-iron 28.2%-

' Recovery Analysis percent mt Pb Zn Fe Pb Zn Fe lstconcentrate 76.2 1.00.5 2nd concentrate..- 1.8 00.5 L9 89 3rdconcentnte. .2 .8 60.2 80railing .03 .08 1.0

It will thus be seen that the lead, zinc, iron and insolubles have beenthoroughly separated. The lauric acid ester of diethylene glycolammonium sulphate employed in this example may be replaced by othercompounds of the types disclosed amounts as the lauric acid ester ofdiethylene glycol ammonium sulphate. The corn oil employed in theexample may be replaced, with substantially the same results, bycottonseed oil, olive oil, palm oil and the like. Sardine oil, menhadenoil and lard oil may also be used although these are not quite sosatisfactoryas the aforementioned oils. Petroleum oils of various gradesgive a somewhat lower selectivity than corn oil or cottonseed oil butmay be preferred in certain instances because of their lower cost.

Example III In another example, involving the separation of :ilmenitefrom a gangue material composed of phosphate, quartz and garnet, the oreanalyzed 1.8% T10: as ilmenite. The ore was ground to pass a 60 meshscreen and conditioned with 0.2 lb. sulphuric acid and 0.1 lb. of ferricammonium sulphate per ton. The pulp, containing 20% solids, was thensubjeced to froth flotation using an emulsion of 2.0% crude oil in waterI containing 1% of mixed coconut oil fatty acid mono esters of glycerolsulphate neutralized with triethanolamine, an amount of the emulsionequivalent to 0.5% of oil per tonof ore being employed. The concentratecontained 37% of TiO:, representing a recovery of 94.5%.

Example IV As still another example, malachite was floated.

from a New Mexico copper ore using an aqueous emulsion containing 1%sardine oil and 1% normal decyl sodium sulphate. The ore contained 1.0%copper and produced an uncleaned concentrateanalyzing 38.2% copper.

The use of emulsions.

as described above, was effective in a slightly acid circuit on chromiteores, rutile ores, hematitc ores, and magnetite ores. In alkalinecircuit, with the addition of copper sulphate, silica, limestone,barite, fluorspar. and magnesite were floated. In some casesparticularly when the minerals were adapted to be freed at relativelycoarse sizes, the froth flotation was effectively replaced byagglomeration or granulation and tabling. In this latter instance,

the first step of the process, namely, selective oiling, was carried outexactly as in the case of the use of emulsions for froth flotation asdescribed I hereinabcve.

Example V An ore of rutile and apatite, containing 3.6% T10: as rutile,was ground to pass through a 20 mesh screen and conditioned in a thickpulp with an aqueous emulsion containing corn oil and mixed coconut oilmono-fatty acid esters of di-' ethylene glycol ammonium sulphate. Using0.4 lb. of the sulphated reagent per ton and 3 lbs. of corn oil per ton,the ore was conditioned by thoroughly mixing. Water was then added toproduce a pulp suitable for tabling. The results are shown in thefollowing table:

Wt. per- T10; per- Pmd'm cent cent Table concentrates '4. l 88. 0 Tabletails 95.9 4.9

As a general rule, it is preferable to add the surface modifying agentfirst in the very thin pulp followed by the addition of the oil and thenthe subsequent dilution of the pulp to the proper density for separationon the table. As illustrative of such practice, the treatment of an ironore may be considered.

Ezample w An ore from the Lake Superior district, containing 30.2% iron,the gangue being silica, was ground to pass through a 14 mesh screen andmixed with a small amount of water, 2.0 lbs. of sulphuric acid and 1.0lb. of the mixed coconut oil fatty acid mono esters of diethylene glycolammonium sulphate per ton of ore. Crude mineral oil in the amount of 6lbs. per ton was then addedand the entire mass mixed. The results, afterdilution and tabling, were as follows:

Wt. pal- Fe per- Pmdm cent cent Table concentrates 51. 2 63. 2 Tabletails 49. 8 8. 2

The process described in Example VI in connection with the concentrationof iron ore may be used on chromite. magnetite, apatite, limestone,dolomite, magnesite and bauxite, without special care in the selectionof the reagentfor the oil. In other cases, however, the selection of theflotation agent is quite critical as, for example, in the separation ofsylvite and halite as they occur in Carlsbad, New Mexico. In this lattercase, where agglomeration procedures are employed. the flotation agentmust be soluble enough to promote oiling but mustselectively aflect thelnterfacial relationship between either the sodium chloride and thepotassium chloride and the brine. Since potassium salts are, in general,moreinsoluble than sodium salts, it is my hypothesis that the flotationagent acts in this case by precipitation of a film of potassium salt.but enough of the flotation agent remains in solution to serve as an oilcarrier. An agent which has produced unusually good results for theseparation of halite and sylvite is mixed coconut oil fatty acid monoesters of diethylene glycol neutralized with ammonia sodium hydroxide,ethanolamines, such as triethanolamine and the like. Other neutralizingagents may be-used but the employment of such agents as indicated abovehas produced very satisfactory results. The process may be carried outaccording to several procedures to produce a mixture of brine, mineraloil and the neutralized mixed coconut oil fatty acid mono esters ofdiethylene glycol sulphate, the oil being selectively adsorbed by thesylvite but not coating the halite, the result being that the sylvite isformed into glomerules of such composition and size that ordinarytabling is sufficient to separate them. The concentrate will consist,'ingeneral, of from 85% to 95% potassium chloride, the tailings containingonly about 5% or less of potassium chloride. The concentrate may beeither dried or otherwise treated to produce a product acceptable foragricultural pu p s Example VII As an example of the separation ofhalite and sylvite, an emulsion was formed of 25 lbs. of crude mineraloil, one lb. of neutralized mixed coconut oil fatty acid mono esters ofdiethylene glycol sulphate and enough brine made from the ore to producea total of 100 lbs. of emulsion. This emulsion was then added to theore, which was in the form of a relatively thin pulp of 12 to 16 meshore,the proportions being such that about 1% to 4 lbs. of the sulphatereagent and 10 to 15 lbs. of oil were present in about one ton of ore.The ore containing the: emulsion was agitated slowly for approximatelyfive minutes until the sylvite agglomerated into particles of sumcientcharacter and size to permit easy separation. The glomerules were easilyobserved so that it could readily be determined whether or not theproduct had advanced to a suitable condition for separation on theseparating table. Although tabling proved very satisfactory for theseparation, any other suitable method of separation commonly used in theore dressing industries can be substituted therefor.

Example VIII In accordance with another method of separating the sylviteand halite, the crude oil was added to a very thick pulp and thesulphate reagent, previously dispersed in a small amount of water, wasintroduced into the pulp. By this method, the amount of the sulphatereagent was reduced to 1.6 lbs. per ton of ore. The results of a testmade in this way are shown in the followingtablei I Total Wt. PercentProduct K01 percent K01 mm Table concentrates 45. 2 y 85 l 95. 2 Tabletails 54.8 4 0 4.8 Composite 100 40 6 100 Example IX In accordance withstill another modification.

of mixed-coconut oil fatty acid mono-esters of diethylene glycolsulphate, thorough stirring being employed to produce a substantiallyuniform mixture. 15 lbs. of crude oil were then stirred into the massand uniformly dispe e therein. Approximately 2000 lbs. of the brine werethen incorporated and the total constituting about 2 tons was tabled. Ahigh-grade concentrate of sylvite, averaging about 90% E01, was obtainedwith only about 5% KC] in the tailings. The. tails may be in partrecirculated to increase the proportionate yield of KCl. The concentratemay be dried in any suitable manner as for example, in air, and may thenbe crushed to give an acceptable agricultural potassium chlorideproduct.

The amount of flotation agent and all employed are not particularlycritical so far as separation is concerned, but, in the interest ofeconomy, it is apparent that no more of the reagent should be used thanis sufllcient to produce satisfactory separation. It is desirable thatnot more than enough oil to wet the sylvite particles should be employedbecause the oil has a tendency to separate out on the table or otherequipment used for separation and this requires periodic cleaning whichcan be avoided if the amount of oil is prop- 1 erly gauged.

While many oleaginous constituents may be employed, the best resultsappear to be obtained if a crude mineral oil, for example, is used. GulfCoastcrude oils, for example, produce particularly good results. Ithasalso been found that ii the crude oil is preliminarily treated to removesome of the voltile constituents, the amount of oil employed in theseparation treatment can be decreased and, in general, somewhat betterresults are obtained. a

Other flotation agents with which satisfactory results have beenobtained in the agglomeration to froth in saturated salt solutions makesthem very valuable reagents for water-soluble salt separations by frothflotation methods and they may be used successfully, for example, in theseparation of boric acid from potassium sulphate, ammonium chloride fromsodium nitrate, sylvite from halite, the concentration of potassiumsulphate and the separation thereof from its associated halite in themineral langbeinite, the separation of salts of barium, lead, zirconium,and ferric iron from salts of potassium, zinc, calcium, magnesium andthe like, and for other water-soluble salt separations.

In carrying out the separation of soluble salts from each other by frothflotation procedures, it is unnecessary to resort to oiling as describedhereinabove. For effecting the separation, for

example, of sylvite from halite by froth flotation without oiling,according to my hypothesis an agent should be used for precipitating aninsoluble potassium salt with a long chain lipophile group outward so asto make the particles water repellent. For this purpose, the alkalimetal or ammonium salts of the fatty alcohol sulphates and sulphonateshaving from 6 to 14 carbon atoms are of utility. of unusual utility isnormal octyl sodium sulphate.

Example X Total Weight KC] Product percent percent KCL'I Cleanerconcentrates 42. 8 95. 6 94. 2

'Middlings 6. 8 25. 2 3. 2 Rougher concentrates- 50. 8 85. 8 98. 8Tailings 49. 2 l. 4 l. 7 Composite 100 42. 9 lot) Since, according to myhypothesis, this flotation action would appear to depend upon theformation of an insoluble potassium salt, the method would be applicableto the separation of any mineral containing a soluble potassium salt.Thus, for example, cement dust containing 10% K20 was concentrated byfroth flotation by adding 2 lbs. of sulphuric acid per ton and 1.2 lbs.of normal octyl sodium sulphate per ton. The concentrate analyzed 48.7%K20.

I have .also found that the flotation of at least many non-sulphideminerals can be inhibited by proper acid concentration. The followingtable, for example, shows the concentrations at which some of the commonminerals are depressed when using a mixture of lauric acid ester ofdiethylene glycol ammonium sulphate and oleic acid as a froth flotationreagent:

H180 per ton p p Mineral Pou nda Rhodochrosite Calcite.

Scheelite; A pat ite. Hematite It will be understood that, while theflotation agents of my invention are very valuable in the flotation ofnon-sulphide minerals, and in this respect represent a distinct advancein the art,

being, of course, recognized that the treatment of different types ofores and minerals may require certain minor modifications and changes.However, in the light of my disclosures herein, it will be evident tothose skilled in the art how to carry out my teachings and producesatisfactory separations.

As previously indicated, the concentration of the flotation agentsemployed is subject to considerable variation, this being dependent uponthe potency of the particular agent selected, the nature of the specificore treated, the degree or character of the separation desired, and uponother factors which are apparent to those versed in the art. In general,concentrations of about .01% up to several per cent of the agent, basedupon the aqueous content of the ore mass being floated, will serve thepurpose, the average case generally requiring from about .05% to 37%.

It will be appreciated that I may employ mixtures of the flotationagents described hereinabove in order to obtain novel eflects. Forexample, while dodecyl sodium sulphate is not quite so selective aslauric acid ester of diethylene glycol ammonium sulphate with respect tocertain types of ores, mixtures of dodecyl sodium sulphate and lauricacid ester of diethylene glycol ammonium sulphate, with or without oleicacid or other similar collectors, can be used to produce a wide varietyof froth textures which can be taken advantage of for the treatment ofparticular ores.

The novel flotation processes which I have described herein areapplicable to the treatment of ores generally. Among the ores which havebeen treated with very good results in accordance with my invention aretungsten ores, lead-zinc-lron ores, oxidized ores such as leadcarbonate, activated blende, kyanite ore, chromite ore. phosphate ores,bauxite, graphite ores, magnetite ores, the separation of silica fromvarious types of ores,

. mica, zirkite ores, rutile ores, cassiterite ores, iron ores, kaolin,coal, and the like.

It will, of course, be understood, particularly in the light of theexamples set forth hereinabove,

that the novel froth flotation and agglomeration reagents of the presentinvention may be employed in conjunction with one or more already knownagents such as collecting agents, frothing agents, depressing agents,emulsifying agents, dispersing agents, activating agents, deactivatingagents, inhibitors, and, in general, organic and inorganic conditioningagents, and the like. These agents include, among'others, mineral andvegetable oils, fuel oil, kerosene, mercaptans, xanthates, organicsulphides, hydrosulphides, carbamates, thiocarbamates, thioureas,di-thiophosphates, azo and diazo compounds, amines such asmonoethanolamine, diethanolamines, triethanolamines and pyridine, alkalimetal and heavy metal soaps, higher fatty acids such as oleic acid andpalmitic acid, sulphonated oils and sulphonated higher fatty acids suchas Turkey red oil and sulphonated oleic acid, gelatin, glue, starch,copper sulphate and other salts of copper, mercury and lead, alkalimetal sulphides such, as sodium sulphide, alkalies such as sodiumhydroxide, potassium hydroxide and sodium carbonate, alkali metalsilicates such as sodium silicate and other agents which are commonlyemployed in flotation and agglomeration processes. It will also beunderstood, as described above, that the flotation circuit may be acidor alkaline depending on the particular ore being separated, the natureof the reagents used and the character of the separations desired. Bycontrolling the pH of the cirruary 13, 1935.

in many cases, be very satisfactorily accom-- plished.

It will be understood that the description of my invention, although,detailed, is to be taken not in a limitative sense but only in adescriptive sense, the scope of my invention being pointed out in theappended claims.

The present application is a continuation-inpart of my priorapplications, Serial No. 879,716, filed July l0, 1933 and Serial No.55,393. flled Feb- What I claim as new and desire to Letteralfatent ofthe United States is:

1. In a process for concentrating non-sulfide protect by minerals byfroth flotation, the step of adding to an ore pulp a proportion of anorganic chemical substance having balanced lipophile and hydrophilegroups, the lipophile group containing at least eight carbon atoms andthe hydrophile group comprising a radical selected from the classconsisting of oxygenated sulphur and oxygenated phosphorusinorganic-acid radicals, and subjecting the pulp to froth flotation.

2. In a process for concentrating non-sulfide minerals by frothflotation, the step of adding to.

an ore pulp a proportion of afatty acid and a proportion of an organicchemical substance hav ,ing balanced lipophile and hydrophile groups,

said lipophile group containing at least eight carbon atoms and thehydrophile group comprising a radical selected from the class consistingof oxygenated sulphur and oxygenated phosphorus inorganic acid radicals,and subjecting the pulp to froth flotation. I

3. In .a process for concentrating non-sulfide minerals by frothflotation, the step of adding to an ore pulp an acid in relatively highconcentration and a proportion of an organic chemical substance havingbalanced lipophile and hydrophile groups, the lipophile groupcontainingat. least eight carbon atoms and the hydrophile group comprising aradical selected from the class consisting of oxygenated sulphur andoiwgenated phosphorus inorganic acid radicals, and subjecting the pulpto froth flotation.

4. In a. process for concentrating non-sulfide minerals by frothflotation, the step of adding to ore pulp an acid, and an organicchemical substance having balanced lipophile and hydrophile groups andhaving the property of foaming in an acid medium, said lipophile groupcontaining at least eight carbon atoms and the hydrophile groupcomprising a radical selected from the class consisting of oxygenatedsulphur and oxygenated phosphorus inorganic acid radicals.

5. In a froth flotation process for concentrating non-sulfide minerals,the step of treating a mass of pulp with an acid to produce a concenandoxygenated phosphorus inorganic acid radi-- cals.

6. In a process for concentrating non-sulfide minerals by flotation, thesteps of acidifying pulp to the equivalent of at least 0.1 lb. ofsulfuric acid per ton, adding oleic acid and an organic chemicalsubstance having balanced lipophile and hydrophile groups, the lipophilegroup having at least eight carbon atoms and the hydrophile anomagroupcomprising a radical selected from the class consisting of oxygenatedsulphur and oxygenated phosphorus inorganic acid radicals, and subject-I ing the ore pulp to froth flotation.

I 7. In a process for concentrating non-sulfide minerals b'y flotation,the steps of acidifying pulp to the equivalent of at least 0.1 lb. ofsulfuric acid p r ton, adding oleic acid and an organic chemicalsubstance having balanced lipophile and hydrophile groups, having atleast eight carbon atoms in the lipophile group and the hydrophile groupcomprising a radical selected from the class consisting of oxygenatedsulphur and oxygenated phosphorus inorganic acid radicals, andsubjecting theore pulp to froth flotation.

8. In a process for concentrating non-sulfide minerals by flotation, thesteps of acidifying pulp to the equivalent of at least 0.1 lb. ofsulfuric acid per ton, adding oleic acid and a sulfuric acidester of ahigher molecular weight aliphatic alcohol, and subjecting the ore pulpto froth flotation, said ester having balanced lipophile and hydrophilegroups.

9. In a froth flotation process for concentrating non-sulfide minerals,the step of treating a mass of pulp with an acid to produce aconcentration equivalent to at least 0.1 lb. of sulfuric acid per ton ofpulp, and adding to the pulp a proportion of free fatty acid and anorganic substance having lipophile and hydrophile groups 'in a state ofbalance in the molecule, the lipophile group having at least eightcarbon atoms and the hydrophile group comprising a radical selected fromthe classconsisting of oxygenated sulphur and oxygenated phosphorusinorganic acid radicals 10. In a froth flotation process forconcentrating non-sulfide minerals, the step of treating a mass of pulpwith an acid to produce a concentration equivalent to at least 0.1 lb.of sulfuric acid per ton of pulp, and adding to the pulp a proportion ofoleic acid and an organic substance having lipophile and hydrophilegroups in a state of balance in the molecule, the lipophile group havingat least eight carbon atoms and the hydrophile group comprising aradical selected from the class consisting of oxygenated sulphur andoxygenated phosphorus inorganic acid radicals.

11. A method of concentrating non-sulfide minerals by froth flotation,which comprises treating a mass of pulp with an inorganic acid toproduce a relatively strong concentration of acid, adding to the pulp anorganic substance having lipophile and hydrophile groups in a state ofbalance in the molecule, the lipophile group containing at least eightcarbon atoms and the hydrophile group comprising a member selected fromthe class consisting of oxygenated sulphur and o ygenated phosphorusinorganic acid radicals, and a relatively small amount of oleic acid,and subjecting the pulp to froth flotation.

' 12. A method of concentrating non-sulfide minerals by froth flotation,which comprises forming a pulp of an ore, incorporating with the pulp aproportion of a frother inthe form of a relatively high molecular weightfatty acid ester of a polyhydroxy substance wherein one of the hydrowgroups of the polyhydroxy substance is replaced by an oxygenatedinorganic acid radical,

together with a relatively small amount of a fatty 4 forming a pulp ofan ore,.incorporating with the pulp'a proportion of a frother in theform of a relatively high molecularweight fatty acid ester of apolyhydroxy substance wherein one of the hydroxy groups of thepolyhydroxy substance is replaced by a sulphonic acid radical. togetherwith a relatively small amount of a fatty acid as a collector, andsubjecting the pulp to froth 15. A method of' concentrating non-sulfideminerals by froth flotation, which comprises forming a pulp of an ore,incorporating with the pulp a proportion of monostearine-sulphoacetateand a relatively small proportion of a fatty acid as a collector, andsubjecting the pulp to froth flotation.

16. In a process for concentrating non-sulfide materials by frothflotation, the step of adding .to an ore pulp a proportion of a chemicalsubstance in the form of a relatively high molecular weight carboxylicacid ester of a polyhydroxy substance wherein at least one hydroxy groupof the polyhydroxy substance is esterifled with an oxygenated inorganicacid radical.

1'7. In a process for concentrating non-sulfide materials by frothflotation, the step of adding to an ore pulp a proportion of a chemicalsubstance in the form of a relatively high molecular weight carboxylicacid ester of a polyhydroxy alcohol wherein at least one hydroxy groupof the polyhydroxy alcohol is esterifled with an oxygenated inorganicacid radical.

18. In a process for concentrating minerals, the step of adding to anore pulp a proportion of a relatively high molecular weight carboxylicacid ester of a polyhydric alcohol wherein one hydroxy group of thepolyhydric alcohol is esterifled with a sulphuric acid radical.

19. In a process for concentrating minerals, the step of adding to anore pulp a proportion of a relatively high molecular weight carboxylicacid ester of a polyhydric alcohol wherein one hydroxy group of thepolyhydric alcohol is esterifled with a sulphuric acid radical, saidsulphuric acid radical being neutralized by an alkaline reactingsubstance.'

20. In a process for concentrating minerals, the step of adding to anore pulp a proportion of a relatively high molecular weight fatty acidester of glycol wherein one hydroxy group of the glycol is esterifiedwith sulphuric acid.

21. In a process for concentrating minerals, the step of adding to anorepulp a proportion of a relatively high molecular weight fatty acidester of glycol wherein one hydroxy group of the glycol is esterifledwith a sulpho-fatty acid of relatively low molecular weight.

22. In the froth flotation of ores the step which comprises utilizing asa flotation agent a compound having the following general formula:

R-XY wherein R is a radical containing a hydrocarbon chain of at least 8carbon atoms,'X is a sulfuric acid or sulfonic acid group present on theextremity of the radical represented by R, and Y is the radical of asalt-forming compound.

23. In the froth flotation of non-sulfide ores the step which comprisesutilizing as a flotation non-sulfide ores in the presence agent acompound having the-following general formula:

R.-X-Y f whereinR represents the residue of a normal primary alcoholcontaining at least- 8 carbon atoms, X represents a sulfuric acid orsulfonic acidgroup, and Y represents the radical of a salt-formingcompound.

' 24. A froth flotation process which comprises agitating and aeratingan aqueous suspension of of a compound having the following generalformula:

R-OSOaNa wherein R represents the residue of a normal primary alcoholhaving from 8 to 18 carbon atoms.

25. A froth flotation process which comprises frothing a suspension ofore in the presence of a fatty acid collecting agent and a compoundhaving the following general formula:

. R'XY wherein R represents a radical containing a hydrocarbon group ofat least 8 carbon atoms, X

represents a sulfuric acid or sulfonic acid group, and Y represents theresidue of a salt-forming compound.

26. A froth flotation process which comprises agitating and aerating anaqueous suspension of non-sulfide ores in the presenceof a fatty acidcollecting agent and a' compound having the following general formula:

nine carbon atoms.

28. In the process of concentrating ores by flotation, the stepcomprising adding to the aqueous flotation medium sodium dodecylsulphate, and subjecting the ore to a flotation separation treatment.

29. In' the process ofconcentrating ores by flotation, the stepcomprising adding to the aqueous flotation medium a salt of a sulphuricacid ester of an aliphatic alcohol having'more than nine carbon atoms,and also adding a known flotation agent, and subjecting the ore to aflotation separation treatment.

30. A froth flotation processwhich comprises agitating and aerating anaqueous suspension of non-sulfide ores in the presence of a collectingagent and a water-soluble compound having the following general formula:

wherein R. represents the residue of a normal primary alcohol containingat least 8 carbon atoms, X represents a sulfuric acid or sulfonic acidgroup and Y represents the residue of a salt-forming compound.

31. A froth'flotation process which comprises agitating and aerating anaqueous suspension of non-sulfide ores in the'presence of a collectingagent and a water-soluble compound having the following general formula:

. R-x---Y wherein R represents the residue of a normal primary alcoholcontaining from 8 to 18 carbon atoms, X represents a sulfuric acid orsulfonic.

acid group and Y represents the residue of a salt-forming compound.

32. A froth flotation process which comprises agitating and aerating anaqueous suspension of non-sulfide ores in the presence of a collectingagent and a water-soluble compound having the following general formula:

R-OSOa-Y 34. A froth flotation process which comprises agitating andaerating an aqueous suspension of non-sulfide ores in the presence of acollecting agent and a water-soluble compound having the followinggeneral. formula:

R-OSOaNa wherein R represents the residue of a normal primary alcoholcontaining from 12 to 18 carbon atoms.

35. The process defined in claim 34 wherein the collecting agent isoleic acid.

36. A process of separating ores by froth flotation which includessubjecting a pulp of the ore to froth flotation in the presence of anorganic nitrogenous substance having lipophile and hydrophile groups ina state of balance in the molecule, the lipophile group having at leasteight carbon atoms.

3'7. A process of separating ores by froth flotation which includessubjecting a pulp of the ore to froth flotation in the presence of anorganic nitrogenous substance having lipophile and hydrophile groups ina state of balance in the molecule, the lipophile group containing ahydrocarbon radical having at least twelve carbon atoms.

38. A process of separating ores by froth flotation which includessubjecting a pulp of the ore to froth flotation in the presence of anorganic nitrogenous substance having lipophile and hydrophile groups ina state of balance in the molecule, the lipophile-group containing astraight chain aliphatic radical having at least twelve carbon atoms 39.A process of separating ores by froth flotation which includessubjecting a pulp of the ore to froth flotation in thepresence of areagent including an organic nitrogen containing halide having ahydrocarbon group containing at least twelve carbon atoms.

40. A process of separating ore by froth flotation which includessubjecting a pulp of the ore to froth flotation in the presence of areagent including an aliphatic hydrocarbon derivative of pyridiniumbromide.

41. A process of separating ores by froth flotation which includessubjecting a pulp of the ore to froth flotation in the presence of areagent comprising an aliphatic hydrocarbon derivative of a pyridiniumhalide.

42. The process of claim 41 wherein the aliphatic hydrocarbon group ofthe reagent contains at least twelve carbon atoms.

43. A process of separating ores by froth flotation which includessubjecting a pulp of the ore to froth flotation in the presence of areagent comprising an aliphatic derivative of a halide of a heterocycliccompound.

44. The process of claim 43 wherein the allphatic hydrocarbon group ofthe reagent contains at least twelve carbon atoms.

45. In the process of concentrating ores by flotation, the stepcomprising adding to the flotation medium a sulphuric acid ester of astraight chain aliphatic alcohol containing at least eight carbon atoms.

BENJAMIN R. HARRIS.

